<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
	</head>
	<body>
		
	</body>
	
	<script>
		/*
		var a = function b(){
			 b = 3;
			 console.log(b);
		}
		a();
		console.log(a);
		b();
		*/
		
		/*
		var a = 1;
		b = function a(x) {
			x && a(--x);
		};
		alert(a); //1
		*/
		
		/*
		function a(x) {
			return x * 2;
		}
		var a;
		alert(a);
		*/
		
		"use strict"; //进入严格模式
		
		function b(x, y, a) {
			a = 20;
			alert(a);
			alert(arguments[2]);
		}
		b(1, 2, 3);
		
		c = 100;

		
	</script>
	
</html>